1. Field of the Invention
The present invention relates to a power supply system. More particularly, the present invention relates to a power supply system for CPU.
2. Description of Related Art
In a computer system, the operating voltage required by the central process unit (CPU) is determined by the dynamic voltage identification code (VID) produced based on the operation mode of the CPU.
FIG. 1 is a block diagram illustrating providing operating voltage to a CPU in the prior art. The operating voltage required by the CPU 101 is not constant all the time. For example, when the CPU 101 enters power saving mode, the operating voltage required is lower than that required when the CPU 191 runs normally. Thus, a dynamic VID is produced by the CPU 101 according to the required operating voltage VCore. Referring to FIG. 1, after producing the dynamic VID, the CPU 101 outputs the dynamic VID to a core voltage controller 103, and then the core voltage controller 103 determines the operating voltage VCore to be provided to the CPU 101 according to the dynamic VID.
However, a new standard will be established to the power supply specification of a new generation CPU by the CPU manufacturer such as Intel company when the new generation CPU is introduced to the market. Thus, the power supply circuit of CPU has to be adjusted almost every year and the variation range thereof varies. The design standard of a new generation CPU is only provided to a few contractors before the CPU is brought into the market by the manufacturer, so that only a few contractors can provide parts supporting the new generation CPU after the CPU has been brought into the market. These parts vendors are not willing to reduce the prices of the products since demand exceeds supply, thus the customers have to pay more money to enjoy the benefit brought by the new technology.
As to those parts vendors who do not sign contract with the CPU manufacturer, the design standard can only be obtained and new parts can only be developed after the new generation CPU and the power supply standard thereof are launched, thus, such vendors fall far behind the contracted vendors and lose many business opportunities. Those manufacturers using the parts of such specification have to bear either the high cost of synchronous development or lose many business opportunities.